1. Denton, D. A. Drive and reinforcement analogs in conversation. Unpublished doctoral dissertation, University of Oklahoma, 1975.
2. Feinberg, R. A., Weiss, R. F., Miller, F. G., Steigleder, M. K., & Lombardo, J. P. Drive as a unifying concept in learned helplessness: Theory and experiments. Unpublished manuscript, University of Oklahoma, 1976. Available from R. F. Weiss, Department of Psychology, University of Oklahoma, Norman, Oklahoma 73019.